Different technologies and approaches to 5G have made it hard for consumers to know what to expect from 5G service. From millimeter wave 5G that is exceptionally fast (but lacking in range) to low-band, high-range 5G that is reminiscent of 4G LTE to mid-band (aka C-band) spectrum, one size does not fit all. But we’ve been here before.
Just like 4G reverting back to 3G during that network evolution, carriers may sometimes need to fall back to 4G LTE coverage from 5G to provide service continuity in areas with coverage gaps or connectivity issues. For example, a mobile device may often be on a carrier’s 5G network in an area that is 5G-equipped — think of an airport or a sports arena. However, going down to the parking lot may cause a device to drop down to a 4G LTE network rather than maintain 5G connectivity.
Despite the challenges, communication service providers continue to invest in 5G technology, and one of the seminal questions in this early investment stage is whether a device is realizing a true 5G experience, or whether it is experiencing “4G leakage.”
Reducing 4G leakage in the transition to Standalone 5G
Today, 5G is still in the roll-out phase. There are many reasons why 5G is still not universal, including a pandemic-induced lack of 5G-enabled chips and sensors and macroeconomic headwinds that have slowed deployments. While many question marks remain, CSPs recognize that the migration to a cloudified 5G SA core will likely not be as fast as initially assumed. A delayed migration will lead to continued reliance on 4G LTE service, which can lead to what is known as 4G leakage.
4G leakage is a function of handover issues between 5G and 4G cells, and that handover can slow down and degrade network performance. We witnessed this in the past with the introduction of 4G and the handover issues between 3G and 4G. Similarly, there are challenges with 5G VoNR (Voice over New Radio) and VoLTE. All that said, we are still in a transitional phase and maintaining continuous voice communications as mobile users move between 4G and 5G cells is still a challenge.
During this evolutionary phase from 4G to 5G, many CSPs are leveraging 4G LTE network infrastructure to offer certain 5G capabilities as they evolve to implement 5G standalone coverage. This capability, 5G Non-Standalone (NSA), has been used most notably by T-Mobile, which is currently the largest deployment of a 5G NSA network in the US. This year, they up-leveled their capabilities and launched a mid-band 5G SA network, which now covers 321 million people across 1.9 million square miles. While this example of 5G SA is still the exception, it illustrates how carriers worldwide can follow suit in the future. By focusing on the continuous deployment of 5G RAN and NSA/SA, it will enable CSPs to increase areas of coverage and network speeds, along with new additions of private 5G and multi-access edge computing (MEC).
As many CSPs are already on their 5G journey and look to cloudify their networks to deliver true 5G SA capabilities, they will need visibility to learn where and when 4G leakage occurs and how it impacts the subscriber and device experience. Mobile operators are looking to a cloudified 5G SA to enable applications such as the automation of ports to manage cargo supply chains or for remote medical usage to accelerate and improve care, and for those and other new applications to make the business case for further investing in 5G. As investment in 5G technology increases, this is the logical next step is for CSPs to invest in tools that identify coverage and performance issues, which will also help mobile operators to accelerate their 5G deployments and improve the overall customer experience. At its heart, building better networks with reduced latency at increased speeds and reliability to enable new Enterprise services is what the promise of 5G has always been about.
